1. Field of the Invention
The present invention relates to portable vehicle service facilities, and particularly to a trailer for performing oil changes and other services on motor vehicles, the trailer having a frame with expandable sides, retractable wheels, and hydraulic vehicle lifts.
2. Description of the Related Art
Traditionally, automotive repair facilities operate from a garage in a fixed location. The garage provides repair personnel with many conveniences not otherwise available, and particularly with a hydraulic post lift for raising the vehicle in order to provide access to the underside of the vehicle for performing oil changes, muffler and exhaust system work, and transmission repairs, among other services. Without access to an automotive service garage, such access normally requires supporting the vehicle on jack stands. While adequate for many purposes, supporting a vehicle on jack stands means working under the vehicle in a cramped area with little room to maneuver. It also requires an adequate surface on which to place the stands, which may not be available, since asphalt or blacktop surfaces tend to crumble under the weight applied to the jack stands.
On the other hand, transporting the vehicle to a service garage at a fixed location is not always convenient. Obviously, when a vehicle requires emergency repairs, it may not be drivable, therefore requiring the expense and inconvenience of towing services. Even where only routine maintenance services are involved, it may still be more convenient and economical to have such services performed on site. An example of the latter situation is the routine servicing of a company's fleet of vehicles, including oil changes, lubrication, tire rotation, etc. It would therefore be desirable to have a portable vehicle service facility equipped with adequate working room and a lift for raising the vehicle above the ground. Several devices have addressed various aspects of this problem.
U.S. Pat. No. 3,931,895, issued Jan. 13, 1976 to S. Grimaldo, describes a collapsible trailer hoist for servicing automobile mufflers on site. The trailer has a frame supported by gravity jacks to take the load off the wheels while the car is driven up ramps onto a pair of tracks which are raised by front and rear pivoting beam arrangements resembling scissors jacks. U.S. Pat. No. 4,238,114, issued Dec. 9, 1980 to P. I. Migliorati, discloses a rocking platform for servicing a vehicle. The device has vehicle support rails mounted on a rocker base. The vehicle is driven up ramps onto the rails, the platform rocking as the vehicle's weight shifts. The device also includes a footpad with arms for removably attaching the footpad to the rails.
U.S. Pat. No. 4,394,877, issued Jul. 26, 1983 to L. Whyte, teaches a system for draining oil from a vehicle on site. The system includes a service vehicle with a waste receptacle mounted on a telescoping track section under the service vehicle. The waste receptacle may be extended under the vehicle to be serviced, which may be raised by ramps or by jack stands. U.S. Pat. No. 4,445,665, issued May 1, 1984 to D. L. Cray, shows a vehicle servicing lift having a frame mounted on wheels bearing a pair of vehicle ramps which are elevated and pivotally supported at their front end by columns. The frame is towed to the work site, the wheels are retracted by a hydraulic cylinder to lower the frame to the ground,the vehicle is driven or winched onto the ramps, and the rear end of the ramps is raised by hydraulic cylinders to support the vehicle in a level position horizontally. The lift is only designed to raise the vehicle three to four feet above ground level.
U.S. Pat. No. 4,724,875, issued Feb. 16, 1988 to Baldwin, et al., describes a trailer mounted lift for performing oil changes having outriggers to support the four corners of the rectangular trailer frame, a pair of ramps sloping from the trailer frame to the ground for loading the vehicle, a pair of tracks mounted on the frame which may be raised by hydraulic cylinders, and outboard extensions so that service personnel may walk around the vehicle while it is raised on the lift.
Less relevant devices including some features of the present invention or for performing a similar function include U.S. Pat. No. 4,350,222, issued Sep. 21, 1982 to Lutteke, et al. (an apparatus for farm vehicles which spreads wheels mounted on drop axles); U.S. Pat. No. 4,772,038, issued Sep. 20, 1988 to N. MacDonald (a trailer which tow three- and four-wheeler sporting vehicles when expanded, but it towed by the sporting vehicles when collapsed); Swiss Patent No. 385,451, published Mar. 15, 1965 (a rocking vehicle lift with parallel tracks mounted on circular sections, the separation between the tracks being adjustable by a hand crank mechanism); and Soviet Invention Certificate No. 458,505, published Mar. 12, 1975 (a device for lifting a vehicle from the side).
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a trailer with expandable sides and retractable wheels solving the aforementioned problems is desired.